package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSON;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private CacheClient cacheClient;
    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient
                .queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);

        //互斥锁解决缓存击穿
        // Shop shop = cacheClient
        //         .queryWithMutex(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //逻辑过期解决缓存击穿
//        Shop shop = queryWithLogicalExpire(id);

        // 逻辑过期解决缓存击穿
        // Shop shop = cacheClient
        //         .queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, 20L, TimeUnit.SECONDS);
        //返回数据
        return Result.ok(shop);
    }

    @Override
    @Transactional
    public Result updateShop(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺id不能为空");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }




//    //缓存穿透
//    public Shop queryWithPassThrough(Long id){
//        String key =CACHE_SHOP_KEY + id;
//        //1.从redis查询数据缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断时是否存在
//        if(StrUtil.isNotBlank(shopJson)){
//            //3.存在直接返回
//            Shop shop = BeanUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//        if(shopJson != null){
//            return null;
//        }
//        //4.不存在，根据id查询数据库
//        Shop shop = getById(id);
//        //5.数据库不存在，空值存入redis
//        if(shop == null){
//            stringRedisTemplate.opsForValue().set(key, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
//        }
//        //6.数据库存在，写入redis，
//        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop));
//        stringRedisTemplate.expire(key, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        //7.返回数据
//        return shop;
//    }

    //缓存击穿
//    public Shop queryWithMutex(Long id){
//        // 1.从redis查询数据缓存
//        String key = CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        // 2.判断缓存是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            // 3.存在直接返回
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//        if(shopJson!=null){
//            return null;
//        }
//        // 4.实现缓存重建
//        // 4.1.判断是否获取互斥锁
//        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
//        Shop shop = null;
//        try {
//            boolean isLock = tryLock(lockKey);
//            if(!isLock){
//                // 4.2.获取锁失败，休眠重试
//                Thread.sleep(50);
//                return queryWithMutex(id);
//            }
//            //4.3成功，根据id查询数据库
//            shop = getById(id);
//            // 5.不存在，返回错误
//            if(shop == null){
//                //将空值写入redis
//                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.MINUTES);
//                //返回错误信息
//                return null;
//            }
//            // 6.存在，写入redis
//            stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop));
//        } catch (InterruptedException e) {
//            throw new RuntimeException(e);
//        } finally {
//            //7.释放锁
//            unLock(lockKey);
//        }
//        return shop;
//    }


//    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
//    public Shop queryWithLogicalExpire(Long id){
//        // 1.从redis查询数据缓存
//        String key = CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        // 2.判断缓存是否存在
//        if (StrUtil.isBlank(shopJson)) {
//            // 3.存在直接返回
//            return null;
//        }
//        //4.命中,需要先把json反序列化为对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        Shop shop = JSONUtil.toBean((JSONObject)redisData.getData(), Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//        // 5.判断是否过期
//        if(expireTime.isAfter(LocalDateTime.now())){
//            //5.1 未过期直接返回
//            return shop;
//        }
//        //5.2 已过期，需要缓存重建
//
//        //6.缓存重建
//        // 6.1.判断是否获取互斥锁
//        String lockKey = LOCK_SHOP_KEY + id;
//        boolean isLock = tryLock(lockKey);
//            //6.2 判断是否获取锁成功
//        if(isLock){
//            //6.3 成功，开启独立线程，实现缓存重建
//            CACHE_REBUILD_EXECUTOR.submit(() -> {
//                try {
//                    //重建缓存
//                    this.saveShop2Redis(id, 20L);
//
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                } finally {
//                    //释放锁
//                    unLock(lockKey);
//                }
//            });
//        }
//        return shop;
//    }
//    //上锁
//    private boolean tryLock(String key) {
//        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
//        return BooleanUtil.isTrue(flag);
//    }
//    //解锁
//    private void unLock(String key) {
//        stringRedisTemplate.delete(key);
//    }

//    public void saveShop2Redis(Long id,Long expireTime) throws InterruptedException {
//        //1.查询店铺数据
//        Shop shop = getById(id);
//        Thread.sleep(200);
//        //2.封装逻辑过期时间
//        RedisData redisData = new RedisData();
//        redisData.setData(shop);
//        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireTime));
//        //3.写入redis
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
//    }

}
